Polyjuice Potion
by eventhestarsdie
Summary: Marauders meets Polyjuice Potion. What happens when Sirius, encased in James Potter's body, has a run in with his mate's long-term crush, Miss Evans?


**Disclaimer: **Unfortunately, I'm not the wonderful J.K. Rowling so I do not own Harry Potter.

**I hope you enjoy this! Please review, I'd love to know what you think :)**

* * *

James swaggered along the corridor coolly. His posture was all wrong, his short hair made his cheeks feel exposed, made him feel exposed, and he kept scrunching up his nose in discomfort. The glasses felt foreign on the bridge of his nose, the world felt smaller around him, and he kept tripping over those bloody massive feet of his.

Maybe because they weren't his at all. Maybe because _he wasn't James_.

It was all Peter's idea. He was the one who suggested they take Polyjuice Potion and pretend to be each other for the day: a "last year of Hogwarts" prank to play on all their fellow students and professors. Of course, nobody else knew and nor would they ever know about it, but that's what made it so precious. The hilarity was all theirs.

And so Sirius was stuck with James and his stupid, uncomfortable glasses. He had hoped for Remus but Peter managed to snatch that one up, although he had at least made the loss worthwhile at breakfast by asking out an unsuspecting Emmeline on Remus' behalf. Sirius couldn't wait to see him try get out of that one.

Classes were now over for the day and dinner was approaching, but all four boys decided to meet up, return to their normal selves, and give "their" clothes and textbooks back to their rightful owners before the meal. Their hideout? The Room of Requirement. It had always been a faithful companion to the boys, regularly helping out by hiding them from Filch on one of his wild goose chases to catch them, or just by providing a nice, secluded spot to plan their next big prank. James often joked that it was the secret, fifth Marauder, and he wasn't far off either. The Room was always wrapped up in their scheming somehow.

Sirius was rounding the last few corners when he felt a delicate hand press nervously against his bicep. Startled out of his daze, he cocked his head to the side to find Lily staring at him with a concerned expression.

"James? Are you ignoring me? I've been calling your name for ages," she said.

Sirius, of course, had been ignoring most people all day just like the other three boys, but not on purpose. They just hadn't quite grasped the fact that they _weren't _in their own bodies. Reminding himself that for the next seven minutes, provided that their time management was up to scratch, he was still James, Sirius beamed that cocky smile that Prongs was so well known for.

"Not at all. My mind was else where, that's all," he replied. _To Lily. Lily Evans. _Then, for the first time that day, he regretted taking the Polyjuice Potion entirely.

He was in _James'_ body, pretending to be _James_, and speaking to the girl that _James_ had been trying to court for years, and suddenly Sirius was very scared he'd muck everything up for his mate.

"Oh, well, good," she said, her concern fading, and a warm smile taking its place. Sirius smiled sharply at her before turning to stalk off to the Room of Requirement; James could make his apologies for the abruptness later. Although, she just took this as an invitation to walk alongside him. _Bloody Evans. _

"So, our fortnightly patrol is tonight. I was wondering, should I wait for you after dinner or meet you in the common room?" she asked.

"Common room is fine."

"Sure." A few moments passed by and Sirius tried to confuse Lily by taking all the sharp corners and weird passages that he knew of on the Seventh Floor, but she was having none of it and time was running out fast. "James, what are you doing?" She quickly rounded Sirius and stopped in front of him, halting him in his tracks. "Trying to get me in one of those alcoves, again?" She smirked. His eyes boggled.

Again? Sirius made a mental note to ask James exactly what "again" meant, and why he hadn't heard of this "again" until now.

"You know, I've been thinking," Lily unfolded her arms and brushed the hair from her eyes with her delicate, slender fingers, "about what you asked me a few weeks back."

James had been _asking her things? _Without Sirius' _knowing? _Sirius made another mental note: to kick James' arse.

"You've changed a lot this year, really matured, and I really-"

He could sense where this was going and he really didn't like it. Of all the days she could pick to have this conversation, it had to be this one, didn't it? "Lily," he warned. She stopped mid-sentence and cocked her eyebrow up at him, confused. "Lily, I'm not- I'm not who you think I am." He winced at how cringe worthy his own words sounded.

A few seconds of silence past before Lily threw her head back and laughed. "What? Wait, don't tell me- Remus is not the only one affected by the full moon. Every month, in the loneliness and solitude of the night, you turn into a giant, bloodthirsty, killer-" She moved closer, so close, and leant down to whisper in Sirius' ear.

"Rabbit."

Lily pulled away and grinned at him and Sirius let his guard down and grinned back up at her because, even to this day, it baffled him at how wonderful Evans' sense of humour was.

She then brushed off the whole joke within seconds and returned to her serious, but in a kind, cuddly sort of way, expression. "C'mon, stop bullshitting Potter, I'm trying to talk to you seriously," she sighed.

"I don't think that's a good idea, Evans," Sirius replied. He worried his bottom lip with his teeth and peered around the corridors for some sort of distraction.

It was like the Marauders had their own distress call because whenever one was in trouble, the others always seemed to appear within seconds. It was then that Sirius heard Peter's voice ringing through the halls, but the words were all James.

"_Padfooooot,_" he sang. The three were out of sight but the sounds of their shoes clicking and clattering against the floor were getting louder. "Siriusly, I _just can't fight this feeeeling any moooore_." James broke out into song as he slid round the corner and extracted sniggers from both Remus and Peter, and also Sirius, who had tried to his best to keep his face solemn as Lily's face soured but he just couldn't.

Lily's face didn't sour because of the singing. No, Peter was a surprisingly nice baritone. It was because she recognised that song; it was a Muggle song that James had taken a fancy to a few months ago and couldn't stop singing ever since. It meant that the person singing had to be James, but it couldn't be, right, because it looked like Peter? And James ignoring her and then saying he wasn't what she thought he was, just when she was about to confess what he'd been wanting for years? She just hoped that he'd taken a liking to the song, and that James was playing it cool, too, because if he didn't, if he wasn't, if her current theory was correct, she was going to be utterly embarrassed.

James, with his stupid grin that didn't quite suit Peter's face, took one look at Lily and turned to stone, mid-swing of the arms and shake of the hips.

Remus, Peter and Sirius tuned in to the severity of the situation and stopped their laughter, suddenly feeling their mouths going completely dry. Lily on the other hand was crossing her arms and looking at each of the four boys, awaiting an explanation that she _yearned _to dismiss her theory.

"Well?" she prompted.

Remus suddenly felt his shirt getting a little tighter and his trousers freely riding up his calves. "We have to go, Lily," he said, his eyes darting with panic and mirroring the fear of the other three. Each of them could feel their last batch of Polyjuice Potion wearing off.

"I'm not leaving until I get an explanation."

"Lily," one of them warned, but she couldn't tell which because they all looked like a mixture of each other by this point. James, Remus and Peter all turned to run, as did Sirius, but Lily managed to catch his arm and hold him back. And the other three couldn't just leave him behind. They were brothers in everything but blood. They stuck together through thick and thin and if one of them was going to be scorned by Lily Evans, well, they'd all just have to bite the bullet and take it.

Lily's eyes grew in shock, sunk in disapproval, and sharpened in anger but they never once left Sirius as he transformed from James Potter back to himself right in front of her. Once it was all over and Sirius was drowning in a shirt and robes two-sized-too-long, she turned her head to the side to find the three other Marauders looking at her, ashamed. The prank might have been funny for them, but it was only ever supposed to be for them, and if anyone else found out then they were in trouble. But if _Lily Evans _found out, then it meant "all over" for James. They were all feeling the current panic and heartbreak and wasted hope of their brother.

"Polyjuice Potion? _Polyjuice_ Potion? Do you know how dangerous that is, especially when brewed incorrectly? What I've you had brewed it wrong and got yourself killed, or any one of them killed for that matter?" She clenched her fist by her side, now turning her entire body around to face James, addressing him and only him as if it were entirely his fault. She felt so stupid, and, to her, it _was_ all his fault. "And to think, I was just coming to accept your proposal of a date. Do you know how stupid I feel? To know that I'd thought you'd grown up and matured away from these stupid, harmful pranks, and to find out that I was completely wrong."

Lily turned to glared at every single one of them, letting them all know that they were equally as immature and stupid as he last. Her eyes landed on Remus. "I would've thought you'd known better, Remus, than to be apart of something so risky. Not to mention illegal," she said, her voice flickering with disappointment- just enough to evoke a serious sense of guilt within him. She knew exactly how to play her boys.

Her eyes were back on James now and were squinting with rage. "Forget about our rounds tonight, Potter. I'll do them by myself. I don't particularly fancy seeing your face around for quite some time," she spat, turning abruptly, her hair whipping her face in the process.

"Lily!" Peter called out, lunging forward slightly and rushing after her, almost tripping over his own feet. It was strange to be back in his own body again. She turned, raising her eyebrow as if to say "well? Make it count."

"It was my idea. All mine, no one elses," he muttered, only loud enough for himself, Lily, and Sirius – seeing as he was standing so close – to hear. "Don't punish him for my foolish mistakes. Yeah, he's stupid for going along with it-" "Well, you haven't got that one wrong-" "Evans!"

This silenced her, so she rolled her eyes as a signal for him to continue. "Yeah, he's stupid, but he's been head over heels with you for years, so go soft on him. Don't hurt him. Don't you dare hurt him," he whispered. It wasn't threatening but more of a plead.

"Whatever, Peter," she drawled after a few moments silence and whipped around again, stalking off and leaving the four boys behind, not knowing what to do.

"She'll come round," Sirius finally chimed. "She always does."

"I don't think she will. Not this time." James looked sad for all of five seconds before his face lit up into a cheery, but fake, smile. All three knew how counterfeit his expression was – it was the classic James In Denial look – but they also knew not to question it and let him pretend for awhile.

"Anyway," Remus began, starting to walk along the corridor and towards the Room of Requirement, "let's get out of these clothes. Merlin, Sirius, who knew you were so small." The sound of laughter rang through the air as Remus pulled at the extremely tight shirt he was wearing.

"Ha, ha," Sirius mocked, but he was smirking nonetheless. Leaning in and dragging Remus back a few feet, letting Peter and James take the lead, he pressed his lips up against the taller boy's ear. "You were pretty adamant last night that I was anything other than _small_," he purred, enjoying the blush that burst out across his cheeks. Sirius let go and cut off all contact, strutting ahead to catch up with the other two as they opened the Room of Requirement.

Talking of blushing…

"Hey, Prongs! Before you got here, Lily happened to mention something about alcoves?" He cocked his eyebrow innocently. "Care to expand?"

The heat radiating from James at that moment could be felt from miles away.


End file.
